Taeniasis and cysticercosis in Asia and the Pacific: present state of knowledge and perspectives

Several topics on taeniasis and cysticercosis in Asia and the Pacific are overviewed. In Asia and the Pacific, three human taeniid species have been recognized: Taenia solium, Taenia saginata and Taenia asiatica. The first topic is on evolution of T. solium. Mitochondrial DNA polymorphisms of T. solium worldwide are discussed with emphasis of two specific genotypes: American-African and Asian. The second topic is recent major advances in sero- and molecular-diagnosis of T. solium cysticercosis in humans, pigs and dogs. The third is the present situation of T. solium taeniasis/cysticercosis in Papua (Irian Jaya), Indonesia. The forth is the present situation of T. solium cysticercosis and T. saginata taeniasis in Bali, Indonesia. The fifth is the present situation of T. asiatica taeniasis in Asia and the Pacific and in North Sumatra, Indonesia. The sixth is on the debate of the exact definition of T. asiatica. Because T. asiatica can not be differentiated from T. saginata morphologically, it is time to re-evaluate T. saginata in Asia and the Pacific. New and broad-based surveys across this region are necessary from epidemiological and public health perspectives, based on evidence.     

Cysticercosis/taeniasis in Asia and the Pacific

Three taeniid tapeworms infect humans in Asia and the Pacific: Taenia solim, Taenia saginata, and Taenia asiatica. Although there is continuing debate about the definition of a new species, phylogenetic analyses of these parasites have provided multiple lines of evidence that T. asiatica is an independent species and the sister species of T. saginata. Here we review briefly the morphology, pathology, molecular biology, distribution and control options of taeniasis/cysticercosis in Asia and the Pacific and comment on the potential role which dogs may play in the transmission of T. solium. Special attention is focused on Indonesia: taeniasis caused by T. asiatica in North Sumatra, taeniasis/cysticercosis of T. solium and taeniasis of T. saginata in Bali, and taeniasis/cysticercosis of T. solium in Papua (formerly Irian Jaya). Issues relating to the spread of taeniasis/cysticercosis caused by T. solium in Papua New Guinea are highlighted, since serological evidence suggests that cysticercosis occurs among the local residents. The use of modern techniques for detection of taeniasis in humans and cysticercosis in humans, pigs and dogs, with the possible adoption of new control measures will provide a better understanding of the epidemiology of taeniasis/cysticercosis in Asia and the Pacific and lead to improved control of zoonotic and simultaneously meat-borne disease transmission.     

NOD-scid mouse as an experimental animal model for cysticercosis

The major three species of human taeniid cestodes, Taenia solium, T. saginata and T. saginata asiatica (= T. asiatica) which require humans as the definitive host are still not rare in developing countries. Among these, T. solium is the most serious with medical and economic importance. Neurocysticercosis (NCC) in humans is now recognized as the major cause of neurologic disease in the world. As these human taeniid cestodes obligatory require domestic animals such as swine, cattle and swine as the major intermediate host animals respectively, it is not easy to analyze the basic research in these domestic animals. In this brief review, we introduce experimental animal model for these three species in order to obtain fully developed metacestode stage in severe combined immunodeficiency (scid) mice. Non-obese diabetic scid (NOD-scid) mice are expected to be a satisfactory animal model and to have advantages for analysis by several view points of developmental biology with gene expression throughout development, antigenic homology of cyst fluid of these three species, evaluation of drug efficacy or metacestocidal drug designs, confirmation of unknown taeniid gravid segments for identification based on the morphology and DNA analysis of metacestodes. The animal model is not only available for human Taenia spp but can also be applied to other taeniid cestodes of economic importance or in veterinary parasitology.     

广西4地带绦虫分离株COX1序列分析

目的 分析广西4地带绦虫分离株COX1序列, 了解亚洲绦虫在广西的分布。方法 对鹿寨、 融水、 田东、 三江等 4县现症病人进行驱虫, 收集绦虫成虫。绦虫成虫经反复洗涤后, 各取孕节一节, 研碎后提取基因组DNA; 同时设计特异性引物, PCR扩增各分离株COX1片段, 对扩增产物进行T?A克隆测序; 应用相关软件分析序列的同源性、 遗传距离, 同时构建系统发生树。同时, 从GenBank检索亚洲绦虫、 猪带绦虫和牛带绦虫COX1基因序列, 并与4地分离株基因序列进行比较。结果 广西4地5个带绦虫分离株的COX1碱基序列长度均为444 bp。鹿寨株与亚洲绦虫之间基因差异为5个位点（1.11%）, 同源性为98.87%, 遗传距离为0.011, 其在邻接法和简约法构建的系统发生树中位于同一分枝。融水A株与猪带绦虫同源性达100%, B株与牛带绦虫和亚洲绦虫的同源性分别达98.20%和96.17%; 田东和三江分离株与猪带绦虫的同源性分别为99.55%和96.40%, 遗传距离分别为0.005和0.037; 鹿寨株与牛带绦虫的同源性达96.40%。结论 广西鹿寨县存在亚洲绦虫流行, 融水县存在牛带绦虫和猪带绦虫混合流行。     

Intestinal cestodes

PURPOSE OF REVIEW: This review summarizes the biology, clinical aspects, diagnosis, treatment and epidemiology for the common and rarer (zoonotic) intestinal cestodes of humans. RECENT FINDINGS: Mass drug application to eliminate Taenia solium carriers may have only temporary effects on cysticercosis transmission. At least two major world genotypes of T. solium have been identified and greater genetic heterogeneity may occur at the regional level. A new human taeniid T. asiatica has been confirmed which occurs sympatrically with T. saginata and T. solium in Southeast Asia. Coproantigen and PCR tests for Taenia spp. have greatly improved diagnostic efficacy and epidemiological studies. There appears to be an increase in human diphyllobothriasis in Europe, Japan and the Americas. SUMMARY: Human intestinal cestode infections are globally primarily caused by species in three genera: Taenia, Hymenolepis or Diphyllobothrium. Sporadic zoonotic infections caused by nontaeniids are usually food-borne or due to accidental ingestion of invertebrate hosts. Intestinal cestode infections generally result in only mild symptoms characterized chiefly by abdominal discomfort and diarrhoea. Most human intestinal cestode infections can be treated with a single oral dose of praziquantel or niclosamide.     

Taeniasis in Mongolia, 2002-2006

Survey on secondary data of taeniasis/cysticercosis was carried out in Mongolia in 2002-2006. A total of 118 taeniid proglottids, a diphyllobothriid segment, and 59 serum samples from 118 taeniasis cases were collected at National Center for Communicable Diseases, Ulaanbaatar, Mongolia. In 2006, 14 serum samples were collected from local people who had histories of epileptic seizures in Selenge Province where pig husbandry was the main business. The 118 proglottids were confirmed to be Taenia saginata by mitochondrial DNA analysis using cytochrome c oxidase subunit 1 and cytochrome b genes. T. saginata taeniasis was widely distributed at least in 10 of 21 provinces. No variation in the nucleotide sequences of the two genes was observed among T. saginata isolates from Mongolia. There was no evidence of Taenia solium taeniasis/cysticercosis or Taenia asiatica taeniasis. A diphyllobothriid segment was confirmed to be Diphyllobothrium latum by mitochondrial DNA analysis.     

Multiple genotypes of Taenia solium--ramifications for diagnosis,treatment and control

Mitochondrial DNA sequences of Taenia solium have fully been analyzed. Analysis of the full length of cytochrome c oxidase subunit 1 (1620 bp) and cytochrome b (1068 bp) genes of T. solium, isolated from Asia (China, Thailand, Indonesia and India), from Latin America (Mexico, Ecuador, Bolivia, Peru and Brazil) and from Africa (Tanzania, Mozambique and Cameroon), has revealed that the two phylogenies obtained were similar to each other regardless of the genes examined. The isolates from Asia formed a single cluster, whereas those from Latin America combined with those from Africa to form an additional cluster. It was estimated that these two genotypes emerged approximately 4-8 x 10(5) years ago. These results together with recent study of the ancient of human taeniid cestodes emerged several MYA in Africa, historical data on swine domestication, distribution of pigs and colonization patterns suggest that T. solium was introduced recently into Latin America and Africa from different regions of Europe during the colonial age, which started 500 years ago, and that T. solium of another origin independently spread in Asian countries, perhaps from China. Why did not T. solium of European origin invade or spread into Asia during the colonial age? Analysis of T. solium distribution must include other Taenia species, especially T. saginata and T. asiatica, which can not be differentiated from each other morphologically. BESS T-base analysis for differentiation of all human Taenia species including the two genotypes of T. solium, and T. saginata and T. asiatica has also been characterized. BESS T-base analysis differentiates African isolates from Latin American isolates as well but more samples should be analyzed for obtaining conclusive evidence for the latter. Serological analysis of cyst fluid of T. solium cysticerci obtained in China and Indonesia and from Mozambique and Ecuador indicates geographical differences in their banding patterns. These differences are discussed in the light of possible differences in pathology of T. solium worldwide. As it has been speculated that the ancient T. solium emerged several million years ago in Africa, it is necessary to analyze more isolates from Africa. Such working hypothesis may be evaluated combined with symptomatology and serology when we get additional DNA data from such areas, since there are some varieties of manifestation of neurocysticercosis with or without subcutaneous cysticercosis and of antigens of cyst fluid of T. solium from Asia and from Africa and/or America. Transfer of techniques of molecular identification and sero- and immuno-diagnoses between researchers and technicians from endemic countries using their own materials should be promoted with the aim of better international cooperation for the control of cysticercosis.     

Taeniasis/cysticercosis in Bali, Indonesia

Taenia solium and Taenia saginata are found in humans in Bali, Indonesia. During a field survey of 660 people in Bali from 2002-2009 of taeniasis/cysticercosis cases using mitochondrial DNA confirmation of the species, we detected 80 cases of T. saginata taeniasis, 2 dual T. saginata/T. solium infections with T. solium metacestodes in the brain and 12 neurocysticercosis (NCC) cases at Sanglah Hospital, Denpasar. Although the prevalence of NCC in Bali is low, sporadic cases are still present. There is no Taenia asiatica in Bali. We summarize here the field survey findings of taeniasis, including 1 dual infection with taeniasis and cysticercosis in 2007, and the reason why there are no T. asiatica cases and we describe 3 NCC cases admitted to Sanglah Hospital, Denpasar, Bali in 2004. Diagnosis was based on anamnesis, clinical examination, including CT Scan, histopathological, serological and mitochondrial DNA examinations. In order to prevent unexpected symptomatic NCC after treatment with praziquantel, we recommend introducing a rapid test to confirm taeniasis carriers and cysticercosis cases as a tool for real time diagnosis.     

云南、贵州两省38条人体带绦虫的分子鉴别

目的对采自云南、贵州两省的38条人体带绦虫进行分子鉴别,了解当地猪带绦虫、牛带绦虫和亚洲带绦虫的分布状况。方法对云南大理和贵州都匀及从江地区有排节片史的病人以槟榔-南瓜子法驱虫,虫体经形态学初步鉴别后,以组织DNA提取试剂盒提取虫体基因组DNA,分别采用亚洲带绦虫、牛带绦虫和猪带绦虫线粒体细胞色素C氧化酶亚单位1基因(cox1)片段的特异性引物对各DNA样品进行常规PCR扩增和琼脂糖凝胶电泳检测;PCR阴性样品采用带绦虫cox1片段PCR通用引物进行扩增,并选择1份亚洲带绦虫特异性PCR阳性的样品作为对照。从3种带绦虫PCR阳性的扩增产物中各选择1份进行核酸序列测定,并用NCBIBlast将各核酸序列与GenBank数据库中带绦虫的cox1进行比对分析。结果采自大理的4条带绦虫(DL1～4)的猪带绦虫cox1片段PCR为阳性,扩增产物约980bp;其余25条大理带绦虫(DL5～29)和5条都匀带绦虫(DY1～5)的亚洲带绦虫cox1片段PCR为阳性,扩增产物约260bp;各样品的牛带绦虫cox1片段PCR均为阴性。DL2PCR产物的核酸序列与GenBank中猪带绦虫cox1的同源性为99%～100%,DY1PCR产物的核酸序列与亚洲带绦虫cox1的同源性为100%。特异性PCR均阴性的4条从江带绦虫(CJ1～4)和亚洲带绦虫特异性PCR阳性的DL7以带绦虫cox1片段通用引物的PCR扩增出约1kb的产物。测序表明,CJ1片段的核酸序列与牛带绦虫cox1的同源性为99%,DL7与亚洲带绦虫cox1的同源性为99%～100%。结论cox1片段PCR扩增和核酸测序分析表明,采集的云南大理人体带绦虫为猪带绦虫和亚洲带绦虫,贵州都匀和从江人体带绦虫分别为亚洲带绦虫和牛带绦虫。     

云南香格里拉的带绦虫rDNA-ITS1序列测定及分析

目的利用分子生物学技术鉴定产于云南香格里拉带绦虫的种类,以明确当地是否存在亚洲带绦虫。方法从云南香格里拉采集带绦虫标本株成虫节片,抽提DNA,PCR扩增rDNA-ITS1区段,克隆此片段后做序列测定;结合GenBank中已知的亚洲带绦虫、牛带绦虫、猪带绦虫rDNA-ITS1序列,经DNAMAN软件处理后计算遗传距离并构建系统发育树状图。结果香格里拉的带绦虫标本与GenBank中已知的亚洲带绦虫序列同源性为99%;与牛带绦虫同源性98%;与猪带绦虫同源性92%。系统发育树显示:香格里拉标本与亚洲带绦虫标本遗传距离最近,距牛带绦虫标本较远,与猪带绦虫则更远。结论云南香格里拉存在亚洲带绦虫。     

分子分类结合形态学方法对云南大理带绦虫的鉴定

目的 鉴定云南大理洱源(E1-E2)、鹤庆(H1-H2)、双廊(SL)、挖色(WS)带绦虫的种.方法 首先对大理分离株带绦虫成虫进行形态学鉴定,从成虫节片中抽提DNA,PCR扩增线粒体DNA细胞色素B(mtDNA-Cyth)的部分序列并测序;结合GenBank中已知猪带绦虫、牛带绦虫和亚洲带绦虫mtDNA-Cytb序列,经DNAMAN软件处理后构建系统发育树状图.结果大理带绦虫E1的形态和牛带绦虫相似,系统发育树显示大理分离株E1、E2、SL、WS带绦虫标本与亚洲带绦虫的遗传距离最接近,距牛带绦虫较远,与猪带绦虫则更远.大理分离株H1、H2带绦虫标本与猪带绦虫的遗传距离最近,距牛带绦虫和亚洲带绦虫则较远.结论 经形态学和分子生物学鉴定,云南大理分离株E1、E2、SL、WS带绦虫标本属于亚洲带绦虫,而H1、H2株带绦虫标本属于猪带绦虫.     

用mtCO技术测定云南及贵州四地区的牛带绦虫

目的　用mtCO技术鉴定云南省大理及贵州省都匀、从江等地所发现的是牛带绦虫或牛带绦虫亚洲亚种。　方法　采集成虫样本,抽提DNA,PCR扩增线粒体细胞色素C氧化酶(mtCO)部分基因片段并测序,经PHYLIP软件包处理,计算遗传距离并构建系统发育树状图。　结果　云南省兰坪、大理和贵州省都匀的标本mtCO基因片段序列与已知牛带绦虫亚洲亚种的序列相同。贵州从江的标本mtCO基因片段序列与已知牛带绦虫的序列相同。两组基因片段的同源性达97.44%,氨基酸序列同源性达99.16%。系统发育树状图显示,牛带绦虫亚洲亚种和牛带绦虫最为接近,远离猪带绦虫及其他绦虫。　结论　云南省兰坪、大理及贵州省都匀存在牛带绦虫亚洲亚种,贵州省从江发现的虫种为牛带绦虫。     

Acute pancreatitis caused by tapeworm in the biliary tract

Taeniasis is a helminthic infection endemic in southeast Asia, including Taiwan. Recent studies suggest that Asian Taenia is a new subspecies of Taenia saginata and has been renamed as Taenia saginata asiatica. It is usually asymptomatic or associated with only mild gastrointestinal symptoms. We report the case of a 52-year-old woman with acute epigastric pain and vomiting. Her levels of amylase and lipase were significantly elevated on admission. Gastrointestinal endoscopy showed proglottids of a tapeworm in the papilla of the duodenum. The epigastric pain subsided and the amylase and lipase levels decreased after removal of the tapeworm by endoscopy and anthelminthic treatment. Although parasites are not an uncommon cause of pancreatitis, especially in disease-endemic areas, it is rare for Taenia to cause acute pancreatitis.     

分子分类结合形态学方法对云南香格里拉带绦虫种类的鉴定

目的鉴定云南香格里拉带绦虫的种类。方法首先对香格里拉株带绦虫成虫进行形态学鉴定;从成虫节片中抽提DNA,PCR扩增rDNA-ITS1区段,克隆测序;结合GenBank中已知的亚洲带绦虫、牛带绦虫和猪带绦虫rD-NA-ITS1序列,构建系统发育树状图。结果香格里拉带绦虫形态学和牛带绦虫相似,测序结果与GenBank中的亚洲带绦虫序列基本一致,同源性分别为99%和100%;系统发育树显示,香格里拉带绦虫与亚洲带绦虫的遗传距离最近,距牛带绦虫较远,距猪带绦虫则更远。结论经形态学和分子生物学鉴定,云南香格里拉株带绦虫属于亚洲带绦虫。     

云南6地域带绦虫mtCOXⅠ片段序列测定分析

目的利用mtCOXⅠ片段的PCR和序列测定鉴定云南6地域（怒江、大理、迪庆、西双版纳、临沧、楚雄）带绦虫的虫种,并构建系统发育树。方法从6地域采集带绦虫成虫,抽提DNA,PCR扩增mtCOXⅠ片段,并做序列测定;结合GenBank中已知的猪带绦虫、牛带绦虫、亚洲带绦虫mtCOXⅠ序列,经DNA MAN软件处理后计算遗传距离并构建系统发育树状图。结果遗传距离矩阵表显示：NJ4、NJ1和DQ2的遗传距离为99.8%,DL4和NJ3的遗传距离为99.5%,NJ2和DQ3的遗传距离为98.8%,DL3与BZ3的遗传距离为98.3%,而与BZ2的遗传距离为96.0%;系统发育树显示：NJ1～4、DL2～3及DQ1～3共10个标本株与BZ3聚为一支.BN1、CX1、LC1与BZ2聚为一支,两支交汇后再与由DL1和BZ1聚合的一支汇合。结论怒江和迪庆各株为亚洲带绦虫,西双版纳、临沧和楚雄株为牛带绦虫,大理株为亚洲带绦虫和猪带绦虫。同虫种不存在地理区域的差异。mtCOXⅠ片段的序列测定可用于带绦虫分类鉴定。     

云南大理白族带绦虫mtDNA-Cytb序列测定及分析

目的利用分子遗传标记对采自云南大理白族地区人体带绦虫标本进行生物多态性的研究。方法从云南大理采集人体带绦虫标本株成虫节片,抽提虫体基因组DNA,PCR扩增线粒体DNA细胞色素B(mtDNA-Cytb)序列部分片段,测序;结合GenBank中已知猪带绦虫、牛带绦虫和亚洲带绦虫mtDNA-Cytb序列,经DNAMAN软件处理后计算遗传距离并构建系统发育树状图。结果大理白族带绦虫标本系统发育树显示大理(B1,B2,B5,B6)株带绦虫标本与亚洲带绦虫的遗传距离最接近,距牛带绦虫标本较远,与猪带绦虫则更远。大理(B3,B4)株带绦虫标本与猪带绦虫的遗传距离最接近,距牛带绦虫和亚洲带绦虫标本远。结论云南大理(B1,B2,B5,B6)株带绦虫标本属于亚洲带绦虫,而(B3,B4)株带绦虫标本属于猪带绦虫;mtDNA-Cytb序列分析可以用于带绦虫生物多态性研究。     

Taeniasis/cysticercosis in a Tibetan population in Sichuan Province, China

The results of a preliminary survey of taeniasis/cysticercosis in Yajiang County, Ganze Tibetan Prefecture in southwest Sichuan Province, China, indicated a very high prevalence of taeniasis (22.5%), with Taenia saginata as the dominant species. There was also a significant occurrence of late-onset epilepsy (8.5% prevalence and 16.4% seropositive for Taenia solium antibodies) attributable in large part to probable neurocysticercosis caused by T. solium. The poor sanitation and hygiene in this Tibetan community likely contributed to a high risk of human cysticercosis despite a low level of T. solium taeniasis (actually no T. solium carriers were detected amongst the 21 proven Taenia carriers). In addition, three taeniasis cases were confirmed by DNA genotyping as Taenia asiatica, which is the first report of this tapeworm in Tibetans, the first report for Sichuan Province and only the third report for mainland China.     

云南保山、普洱带绦虫mtDNA ND1基因序列测定及分析

目的对云南保山、普洱地区带绦虫标本进行鉴定。方法选取带绦虫成虫节片,抽提虫体基因组DNA ,PCR扩增mtDNA ND1基因序列,并测序;结合GenBank中已知的亚洲带绦虫、牛带绦虫、猪带绦虫mtDNA ND1基因序列,经DNA MAN软件处理后构建系统发育树状图与同源树状图。结果带绦虫系统发育树与同源 树状图显示P1、P2、B3、B6、B7、ND与N2的同源性最近。B1、B2、B4、B5、YZ与Y1的同源性最近。ZD与Z3 的同源性最近。结论云南保山存在亚洲带绦虫与牛带绦虫;普洱存在牛带绦虫。mtDNA ND1基因序列可用 于三种带绦虫的分类鉴定。     

A Cross-Sectional Study of Taenia solium in a Multiple Taeniid-Endemic Region Reveals Competition May be Protective

Abstract. We conducted cross-sectional surveys for taeniasis and cysticercosis in humans, pigs, and dogs in four northern provinces of Laos. Human cysticercosis and taeniasis prevalence was 2.2% (95% confidence interval [CI] = 1.4-3.0%) and 8.4% (95% CI = 6.9-9.9%), respectively. Eating uncooked beef, being male, province of residence, age, and ethnicity were significant risk factors for taeniasis and only province of residence was a significant risk factor for cystiercosis. Thirty-five human tapeworms were recovered during the survey and 33 (94.3%) and 2 (5.7%) were identified as Taenia saginata and T. solium, respectively. Maximum-likelihood adjusted prevalence of T. solium and T. hydatigena in pigs was 4.2% (95% CI = 0.5-7.9%) and 55.9% (95% CI = 47.5-64.3%), respectively, and T. hydatigena taeniasis in dogs was 4.8% (95% CI = 0.0-11.3%). Taenia hydatigena and T. saginata were the most prevalent taeniids in the respective pig and human populations and together may suppress T. solium transmission.     

云南保山和普洱地区带绦虫线粒体DNA基因编码核糖体RNA小亚基基因序列分析

目的 利用线粒体DNA基因编码核糖体RNA小亚基(mtDNA-12S rRNA)基因序列分析对采自云南保山、普洱地区的带绦虫标本进行鉴定.方法 选取保山(7条,BS1-BS7)、普洱(2条,PE1～PE2)带绦虫成虫节片,抽提基因组DNA,PCR扩增mtDNA-12S rRNA基因序列,并测序;结合GenBank中已知的猪带绦虫(ZD)、牛带绦虫(ND)、亚洲带绦虫(YZ)mtDNA-12S rRNA基因序列,经DNA MAN软件处理后构建同源树状图与系统发育树状图.结果 带绦虫同源树与系统发育树状图显示,BS1、BS2、BS4、BS5与YZ的同源性最近(99%).BS3、BS6、BS7、PE1、PE2与ND的同源性最近(99%).结论 云南保山存在牛带绦虫与亚洲带绦虫,普洱存在牛带绦虫,mtDNA-12S rRNA基因序列可用于三种带绦虫的分类研究.

Abstract：

Objective To identify Taenia cestodes specimens collected from Baoshan and Puer regions of Yunnan Province by analyzing mitochondrial DNA gene encoding ribosomal RNA small subunit (mtDNA-12S rRNA) gene sequence. Methods The adult Taenia cestode samples were collected from Baoshan and Puer regions of Yunnan Province. The genomic DNA was extracted and mtDNA-12S rRAN gene was amplified by polymerase chain reaction (PCR), then sequenced.Combined with the known mtDNA-12S rRNA gene sequence of Taenia solium, Taenia saginata,Taenia asiatica in GenBank, homology tree and phylogenetic tree were constructed by DNA MAN software. Results Taenia cestode homology tree and phylogenetic tree showed that gene sequences of BS1, BS2, BS4 and BS5 were most close to YZ with identity of 99% and those of BS3, BS6, BST,PE1 and PE2 were most close to ND with identity of 99%. Conclusions Taenia saginata and Taenia asiatica can be found in Baoshan area, while Taenia saginata can be found in Puer area. The gene sequence of mtDNA-12S rRNA can be used for clarifying the three types of Taenia cestode.